COVENTRY, England — Studies linking sitting down for long periods of time to early death and numerous ailments have cropped up more and more in recent years, and now new research finds desk jobs are linked to larger waist sizes and a raised risk of heart disease.
The study, based out of the University of Warwick in England, had 111 healthy postal workers — 55 who had desk duties and 56 who were mail carriers — from Glasgow, Scotland wear activity monitors strapped to their thighs for a week. Participants provided blood samples and had their vitals measured in a physical examination.
Researchers found that those who worked in the office had a larger waist circumference (3 centimeters bigger on average) and a greater risk of heart disease (2.2% compared to 1.6% over ten years.) The postal carriers also had a lower body mass index (BMI) by one unit.
“Longer time spent in sedentary posture is significantly associated with larger waist circumference, higher triglycerides (fat in the blood) and lower HDL cholesterol, all adding up to worse risk of heart disease,” says Dr. William Tigbe, who led the research at the university’s medical school, in a release.
In fact, Tigbe and his team concluded from the study that a person’s waist size increases by two centimeters, or a touch more than three-quarters of an inch, for every hour spent sitting after five hours. The risk of heart disease spikes by 0.2% per additional hour as well, while LDL, or bad cholesterol, was found to increase and HDL, or good cholesterol, decreased.
Tigbe says a key number for healthy people is seven: that is, to show no risk factors for heart disease, people should walk at least seven miles per day (or 15,000 steps), and should spend at least seven hours standing up.
“Our findings could be used as the basis of new public health targets for sitting, lying, standing and stepping to avoid metabolic risks,” he says. “However the levels suggested in our research would be very challenging to achieve unless incorporated into people’s occupations.”
Professor Mike Lean of the University of Glasgow’s School of Medicine, who also worked on the study, believes the findings represent the types of activities human beings were built for.
“Our evolution, to become the human species, did not equip us well to spending all day sitting down. We probably adapted to be healthiest spending seven to eight hours every day on our feet, as hunters or gatherers,” he says.
The researchers hope the study will play into healthcare policies and perhaps send a message to employers concerned about their employees’ wellness. It also gives people a benchmark for physical activity to avoid heart disease.
Adds Lean: “The ‘bottom’ line is that if you want to be sure of having no risks of heart disease, you must keep off your bottom!”
The study was published in the International Journal of Obesity.